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검색결과 9,967건 처리시간 0.041초

Hyperbaric oxygenation applied before or after mild or hard stress: effects on the redox state in the muscle tissue

  • Claudia Carolina Perez-Castro;Alexandre Kormanovski;Gustavo Guevara-Balcazar;Maria del Carmen Castillo-Hernandez;Jose Ruben Garcia-Sanchez;Ivonne Maria Olivares-Corichi;Pedro Lopez-Sanchez;Ivan Rubio-Gayosso
    • The Korean Journal of Physiology and Pharmacology
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    • 제27권1호
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    • pp.9-20
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    • 2023
  • The mechanism is unclear for the reported protective effect of hyperbaric oxygen preconditioning against oxidative stress in tissues, and the distinct effects of hyperbaric oxygen applied after stress. The trained mice were divided into three groups: the control, hyperbaric oxygenation preconditioning, and hyperbaric oxygenation applied after mild (fasting) or hard (prolonged exercise) stress. After preconditioning, we observed a decrease in basal levels of nitric oxide, tetrahydrobiopterin, and catalase despite the drastic increase in inducible and endothelial nitric oxide synthases. Moreover, the basal levels of glutathione, related enzymes, and nitrosative stress only increased in the preconditioning group. The control and preconditioning groups showed a similar mild stress response of the endothelial and neuronal nitric oxide synthases. At the same time, the activity of all nitric oxide synthase, glutathione (GSH) in muscle, declined in the experimental groups but increased in control during hard stress. The results suggested that hyperbaric oxygen preconditioning provoked uncoupling of nitric oxide synthases and the elevated levels of GSH in muscle during this study, while hyperbaric oxygen applied after stress showed a lower level of GSH but higher recovery post-exercise levels in the majority of antioxidant enzymes. We discuss the possible mechanisms of the redox response and the role of the nitric oxide in this process.

Variables affecting strain sensing function in cementitious composites with carbon fibers

  • Baeza, F.J.;Zornoza, E.;Andion, L.G.;Ivorra, S.;Garces, P.
    • Computers and Concrete
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    • 제8권2호
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    • pp.229-241
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    • 2011
  • In this work, cement paste samples with 1% (by cement mass) of a conductive carbon fiber admixture have been studied under uniaxial compression. Three different arrangements were used to measure the resistivity of the samples. According to the results obtained, the resistance should be measured using the four wire method in order to obtain good sensitivity and repeatability. The effect of the load value and the load rate on the fractional change of the volume resistivity has been determined. It has been observed that the gage factor (fractional change in resistance respect to strain) increases when the maximum load is increased, and the loading rate does not affect significantly this parameter. The effect of the sample ambient humidity on the material piezoresistivity has also been studied, showing that the response of the composite is highly affected by this parameter.

조선건국초 인서문화의 의의 (LA SIGNIFICATION DE LA CULTURE DU LIVER IMP RIME AU DEBUT DE LA DYNASTIE DE CHOSON)

  • 이희재
    • 한국문헌정보학회지
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    • 제13권
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    • pp.121-142
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    • 1986
  • Au debut de la dynastie de Choson, qui represente une periode de la regne des rois T'aejo et T'aejong, il fallait etablir et codifier la .nouvelle politique nationale, et c'est dans ce contexte que les caracteres kyemi, qui ont joue Ie role tres important dans l'histoire de la typographie mondiale, furent crees. Le sujet de ce memoire n'est qu'une enumeration des faits historiques de l'edition ou de l'imprimerie dans cet epoque, mais une recherche sur la vraie signification de la culture du livre imprime. Done, on peut etudier ici; d'abord, less activites de l'imprimerie a l'epoque du roi T'aejo et du roi T'aejong, et enfin, la signification et le bilan synthetique de ces activites, surtout des caracteres kyemi sur le point de l'histoire de la civilisation mondiale.

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Synthesis and Cations Binding Properties of a New C,N-bipyrazolic Ligand

  • Attayibat, Ahmed;Radi, Smaail;Ramdani, Abdelkrim;Lekchiri, Yahya;Hacht, Brahim;Bacquet, Maryse;Willai, Stephanie;Morcellet, Michel
    • Bulletin of the Korean Chemical Society
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    • 제27권10호
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    • pp.1648-1650
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    • 2006
  • The synthesis of a new C,N-bipyrazolic ligand with a functionalized donor-group is reported. The binding properties of the ligand and two other ligand of similar structures towards heavy metal ions ($Hg^{2+}$, $Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$) and alkaline metal ions ($K^+$, $Na^{+}$, $Li^+$) were studied by a liquid-liquid extraction process and the extracted cation percentage was determined by atomic absorption measurements. The selectivity of the ligand to Hg(II) has been mentioned in the abstract.

ER-mediated stress induces mitochondrial-dependent caspases activation in NT2 neuron-like cells

  • Arduino, Daniela M.;Esteves, A. Raquel;Domingues, A. Filipa;Pereira, Claudia M.F.;Cardoso, Sandra M.;Oliveira, Catarina R.
    • BMB Reports
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    • 제42권11호
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    • pp.719-724
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    • 2009
  • Recent studies have revealed that endoplasmic reticulum (ER) disturbance is involved in the pathophysiology of neurodegenerative disorders, contributing to the activation of the ER stress-mediated apoptotic pathway. Therefore, we investigated here the molecular mechanisms underlying the ER-mitochondria axis, focusing on calcium as a potential mediator of cell death signals. Using NT2 cells treated with brefeldin A or tunicamycin, we observed that ER stress induces changes in the mitochondrial function, impairing mitochondrial membrane potential and distressing mitochondrial respiratory chain complex Moreover, stress stimuli at ER level evoked calcium fluxes between ER and mitochondria. Under these conditions, ER stress activated the unfolded protein response by an overexpression of GRP78, and also caspase-4 and-2, both involved upstream of caspase-9. Our findings show that ER and mitochondria interconnection plays a prominent role in the induction of neuronal cell death under particular stress circumstances.

First Evaluation of an Outbreak of Bovine Babesiosis and Anaplasmosis in Southern Brazil Using Multiplex PCR

  • Canever, Mariana Feltrin;Vieira, Luisa Lemos;Reck, Carolina;Richter, Luisa;Miletti, Luiz Claudio
    • Parasites, Hosts and Diseases
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    • 제52권5호
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    • pp.507-511
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    • 2014
  • Outbreaks of tick-borne disease cases in Santa Catarina, Brazil are known, but the presence of the pathogen DNA has never been determined. In this study, the first survey of Anaplasma marginale, Babesia bigemina, and Babesia bovis DNA on blood samples of 33 cattle from an outbreak in Ponte Alta Municipality, Santa Catarina, Brazil, has been carried out. A multiplex PCR detected 54.5% of animals were co-infected with 2 or 3 parasites, while 24.2% were infected with only 1 species. The most prevalent agent was B. bigemina (63.6%) followed by A. marginale (60.6%). This is the first report of tick-borne disease pathogens obtained by DNA analysis in Southern Brazil.

Topological optimization procedure considering nonlinear material behavior for reinforced concrete designs

  • Franca, Marcela Bruna Braga;Greco, Marcelo;Lanes, Ricardo Morais;Almeida, Valerio Silva
    • Computers and Concrete
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    • 제17권1호
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    • pp.141-156
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    • 2016
  • The search for new structural systems capable of associating performance and safety requires deeper knowledge regarding the mechanical behavior of structures subject to different loading conditions. The Strut-and-Tie Model is commonly used to structurally designing some reinforced concrete elements and for the regions where geometrical modifications and stress concentrations are observed, called "regions D". This method allows a better structural behavior representation for strength mechanisms in the concrete structures. Nonetheless, the topological model choice depends on the designer's experience regarding compatibility between internal flux of loads, geometry and boundary/initial conditions. Thus, there is some difficulty in its applications, once the model conception presents some uncertainty. In this context, the present work aims to apply the Strut-and-Tie Model to nonlinear structural elements together with a topological optimization method. The topological optimization method adopted considers the progressive stiffness reduction of finite elements with low stress values. The analyses performed could help the structural designer to better understand structural conceptions, guaranteeing the safety and the reliability in the solution of complex problems involving structural concrete.